Power presses



April 21, 1970 COUPLAND ETAL 3,507,142

- POWER PRESSES Filed July 19. 1966 s sheets-sheet '1 A iil 21, 1970 @Q L TAL 3,507,142

POWER rnnssEs 5 Sheets-Shet 2 Filed July 19. 1966 United States Patent US. Cl. 72-415 2 Claims ABSTRACT OF THE DISCLOSURE In the manufacture of a pressing of channel, trough, or similar concave section having spaced upstanding edges, after the pressing has been formed between a punch and a die it is forced into close conformity with the die by a plurality of hammer blows applied to the upstanding edges of the pressing.

This invention relates to improvements in power presses for the production of presssings such, for example, as axle casings, in which a movable punch or like forming tool cooperates with a die for forming a metal sheet or strip into a pressing having spaced upstanding edges.

The metal from which pressings are usually formed has a certain amount of resilience even when the metal is hot, and where a pressing is formed by a simple pressing operation in a die and punch the recovery of the metal on separation of the tools may be such that the pressing does not conform accurately to the contour of the die.

In the specification of our British Patent No. 757,634, there is described and claimed a tool for forming pressings having spaced upstanding edges in which the forming tool comprises a punch nose to co-act with the die in shaping the component so that its edges will be upstanding at the desired angle and a punch body for bearing on the upper surfaces of the edges of the pressing at an approximate pressure during the latter part of the forming operation while the punch nose partially withdraws into the punch body.

According to our present invention, the two operations described above of forming a component and applying pressure to the edges of the component are not carried out as a smooth sequence of operations but are divided into two.

The component is first formed by advancing the ram of the press with the punch nose extended until the component is fully embedded in the die. The ram of the press is then retracted a short distance while at or about the same time the punch nose is withdrawn into the punch body and held in that position. The ram of the press is then advanced at high speed to enable a coining operation to be carried out on the upstanding edges of the pressing. This coining operation or hammer blow can be repeated a number of times if required.

The essential parts of a power press for carrying out in accordance with our invention the formation of a pressing such as an elongated axle casing of trough or like section are illustrated diagrammatically by way of example in the accompanying drawings in which:

FIGURE 1 is a front elevation in part section;

FIGURE 2 is a transverse section showing the parts in their normal inoperative positions, the section being ice taken in two parallel planes on opposite sides of the centre line;

FIGURE 3 is a transverse section showing the parts in the positions corresponding to the initial part of the formation of the pressing;

FIGURE 4 is a transverse section showing the next position of the parts with the punch nose retracted, the section being taken in two parallel planes on opposite sides of the centre line as in the case of FIGURE 2; and

FIGURE 5 is a transverse section showing the parts in the positions corresponding to the final coining operation.

In the drawings 10 is the vertically movable rarn of an hydraulic press to which a main bolster 11 is rigidly but detachably secured. The length of the ram and bolster is greater than that of the pressing to be formed, and the press is capable of effecting high speed downward movements of the ram and the parts carried by it.

Below the main bolster 11 there is a top tool bolster 12 in which is mounted for vertical movement therein an elongated punch beam 13 carrying a punch nose 14 corresponding to the internal form of the pressing to be made.

The fixed base or bed 15 of the press carries a bottom bolster 16 in which is mounted an elongated bottom die or die steel 17 having a cavity corresponding to the external form of the pressing.

Ejector pins 18 for ejecting the finished pressing from the die are mounted in the bottom bolster and die steel and are backed by cushion pins 19 which are actuated in any convenient known manner.

The punch beam 13 is supported from the ram 10 by spaced vertical bolts 21 of which the lower ends are screwed into or otherwise secured to the punch beam. At their upper ends the bolts pass through and are secured in pistons 22 working in vertical cylinder bores 23 in the ram. Fluid under pressure can be supplied either above or below the pistons to apply an upward or downward pressure to the bolts.

The punch beam is actuated by six pistons 24 working in longitudinally spaced vertical cylindrical bores 25 in the bolster 11. Each piston has on its lower end a spigot extension 26 working in a reduced extension of the bore 25 and acting on the upper side of the beam through tubular thimbles or distance-pieces 27. The upper end of each bore 25 is occupied by a fixed block or sleeve 28 of which the upper end is bored to form a cylinder in which works a truncated piston 29 adapted to bear on a vertical pin 30 extending downwardly through the piston 24. The pin 30 in turn is adapted to bear on an aligned knock-out pin 30a which extends downwardly through the punch beam 13 and punch nose 14 for stripping the pressing from the punch nose.

Hydraulic fluid under pressure can be supplied to each bore 25 above the piston 26 to urge the punch beam downwardly or below the shoulder 31 on the piston to raise it.

The lower end of the punch beam extends through coining steels 32 located on opposite sides of the beam. The width of the punch beam is less than that of the punch nose and the Width of the lower face of each coining steel is slightly greater than the wall thickness of the pressing, the total width over the lower faces of the steels being substantially equal to the spacing between opposite sides of the die 17 on its open upper face.

Initially the various parts are in the positions shown in FIGURE 2, while a sheet metal blank 33 is placed in position over the die 17. The ram of the press is lowered to the position shown in FIGURE 3 and fluid under pressure is admitted to the bores 25 above the pistons 24 which force the punch beam and punch nose downwardly to force the blank 33 into the die. The total force applied to the blank is the sum of the hydraulic forces acting on the six pistons 24.

This force is sufiicient to overcome the upward force exerted on the bolts 21 by fluid pressure under the pistons 22.

The press ram is then raised through a short distance while the spaces in the cylinder 25 above the pistons 24 are connected to exhaust and fluid under pressure is supplied below the shoulders 31 on the pistons. At the same time the hydraulic load on the bolts 21 urges the punch beam upwardly and fluid under pressure is admitted above the pistons 29 for the knock-out pins 30a so that the pins are projected downwardly and strip the pressing ofi the punch nose if it should tend to come up with the punch nose.

Then while the punch beam is held in its raised position in the tool bolster 12 the main hydraulic cylinder of the press takes over and brings down the ram at high speed so that the steels 32 strike the upstanding edges of the pressing as shown in FIGURE 5 to perform a coining operation on the pressing and force it into full conformity with the die. This coining operation may be repeated two or more times as required.

The steels 32 at the same time shape the edges of the pressing for further operations such as welding.

In the form illustrated the operative faces of the steels are flat and horizontal but they may be inclined if it is desired that the edges of the pressing should be bevelled to form with those of a similar pressing a V notch to receive weld metal.

It will be appreciated that all the steps in making the pressing will normally be controlled automatically in 4 sequence so that the operator has only to place the blank in the press and remove the finished pressing, and even these operations can be performed by further means operated automatically in synchronism with the press.

What is claimed is:

1. Apparatus for producing a pressing of channel, trough and similar concave sections, comprising a power press including a vertically movable ram, a main bolster carried by the ram, 21 top tool bolster carried by the main bolster, a punch beam mounted for vertical movement in the tool bolster, hydraulic cylinder and piston means located in the main bolster for moving said punch beam vertically in the tool bolster, a punch nose carried by the punch beam, coining steels mounted on the underside of the tool bolster on opposite sides of said punch beam, a stationary bottom bolster, and a die mounted in said bottom bolster for cooperation with said punch nose.

2. Means as claimed in claim 1 further including hydraulically operated means for stripping the pressing from the punch nose and hydraulically operated vertically movable bolts coupling the punch beam to the press ram.

References Cited UNITED STATES PATENTS 1,879,078 9/1932 Carlsen 72-415 2,120,595 6/1938 1 Ash 72-356 3,152,393 10/1964 Johnson 72-415 866,026 9/ 1907 Hansen 72354 RICHARD J. HERBST, Primary Examiner US. Cl. X.R. 

